1. Field of the Invention
The present invention relates to a light-emitting device and a manufacturing method thereof. In particular, the present invention relates to a light-emitting device with a curved surface.
2. Description of the Related Art
Research and development have been extensively conducted on organic EL (electroluminescence) elements. In the fundamental structure of the organic EL element (hereinafter, also referred to as EL element or light-emitting element), a layer containing a light-emitting organic compound is provided between a pair of electrodes. By applying voltage to this element, light emission from the light-emitting organic compound can be obtained.
The light-emitting device using the organic EL element is, for example, a lighting device, or an image display device including a combination of thin film transistors.
The organic EL element can be formed into a film shape; thus, a large-area element can be easily formed. Therefore, the organic EL element has a high utility value as a surface light source that can be applied to lighting or the like. For example, a lighting device including an organic EL element is disclosed in Patent Document 1.
In addition, an image display device using the organic EL element needs no backlight which is necessary for a liquid crystal display device and the like; therefore, thin, lightweight, high contrast, and low power consumption display devices can be obtained.
As a method for forming a layer containing a light-emitting organic compound over a lower electrode formed over a substrate having an insulating surface when the organic EL element is formed, a vacuum evaporation method, a coating method, or the like is given, for example. As a method for forming the lower electrode and the upper electrode, a vacuum evaporation method, a sputtering method, a coating method, a printing method, or the like is given.
In recent years, diversification of shape of light-emitting device has been required. One example is a light-emitting device having a curved surface. By giving a light-emitting device a curved surface, the design and general versatility are improved, so that degrees of freedom of installation location and shape of incorporated members are improved. For example, a lighting device or a display device can be incorporated along a curved surface of the interior or exterior of a building or a car. In addition, the light-emitting device can be used for various applications; a wearable lighting device or display device such as a wristband, a portable terminal such as a mobile phone and a tablet terminal having a curved display portion, and the like can be given.